In this paper, a double-temperature refractive index model, which can be used to simultaneously obtain the temperatures of the electron and gas for plasma, is introduced. In addition, the rationality and superiority of the proposed model are theoretically discussed. Furthermore, argon arc plasmas with different injected pressures are selected as practical examples for experiments. During the experiments, refractive index measurements are performed using two-wavelength moiré tomography with probe wavelengths of 532 nm and 808 nm. The region division of the measured argon plasmas is achieved using emission tomography. Finally, the temperatures of the electron and gas are reconstructed to verify the feasibility of the double-temperature refractive index model, and the factors that might cause imprecision are analyzed. The findings of this study will be valuable for expanding the applicable region of optical computerized tomography methods and facilitating optical diagnosis in plasma flow fields .